British English : UN The UN is an organization which most countries belong to. Its role is to encourage international peace, cooperation, and friendship. UN is an abbreviation for `United Nations'....a UN peacekeeping mission.juː ɛn ABBREVIATION
abbreviation for
United Nations
pronoun
a spelling of one ⇒ that's a big 'un
prefix
(freely used with adjectives, participles, and their derivative adverbs and nouns: less frequently used with certain other nouns) not; contrary to; opposite of ⇒ uncertain , uncomplaining , unemotionally , untidiness , unbelief , unrest , untruth
prefix forming verbs and verbal derivatives
denoting reversal of an action or state ⇒ uncover , untangle